1. Technical Field
The present disclosure relates to a sound pick-up device which collects sound, and an imaging device including the sound pick-up device.
2. Description of the Related Art
Conventionally, there is known a sound processing device which has an auto level control (ALC) function by which the magnitude of input sound is controlled at an appropriate level (for example, see Patent Literature 1).
Unexamined Japanese Patent Publication No. 2000-4494 discloses a microphone device which reduces an internal noise being mixed when an external sound is being collected, where an equipment housing contains a mechanism which generates noise when the equipment is operated. This microphone device is equipped with: a main microphone which collects an external sound coming from the outside of an equipment housing; a noise reference microphone provided in the inside of the equipment housing; an adaptive filter which acquires a signal detected by the noise reference microphone and generates a control sound signal by using a renewed filter coefficient; a signal subtractor which subtracts the control sound signal of the adaptive filter from an output signal of the main microphone; a signal level comparator which compares a level of the output signal of the main microphone and a level of the detected signal of the noise reference microphone; and a filter coefficient renewal controller which acquires a comparison result of the signal level comparator, a subtraction result of the signal subtractor, and the detected signal of the noise reference microphone and which renews, when an output level of noise reference microphone is greater than an output level of the main microphone, the filter coefficient of the adaptive filter so that the subtraction result of the signal subtractor becomes minimum. Because this microphone device gives a signal from the noise reference microphone to the adaptive filter to generate the control sound signal and cancels noise by this control sound signal; thus, it is possible to reduce an internal noise being mixed in at the time of collecting an external sound.